Heavy fuel engine



y 1939- H. v. HONN 2,158,124

HEAVY FUEL ENGINE I Filed May 4. 1937 4 zil" 1 22 2f 7 7 I N V EN TOR,

HARL AN VERNE HON/.V.

Patented May 16, 1939 UNITED STATES PATENT OFFICE HEAVY FUEL ENGINEHarlan Verne Honn, San Francisco, Calif.

Application May 4, 1937, Serial No. 140,662

8 Claims. (01. 123-1431 My invention relates to heavy fuel engines, andmore particularly to engines wherein a charge is ignited before beingprojected into a work cylinder. This application is a continuation inpart of my co-pending application, Serial No. 745,573,

filed September 26, 1934.

In my co-pending application referred to above, I have described andclaimed an internal combustion engine wherein two separate cylinders are10 utilized, these cylinders being of different sizes. The smallercylinder I term an igniter cylinder, and in that cylinder I compress andfire by compression an extremely rich charge of fuel. The burning chargeis then by-passed into the larger work cylinder where it mixes with anair charge and completes its combustion with the proper fuel-airmixture.

The present invention concerns a similar engine, differing, however, ina number of features from that described in my prior application,although the general theory of operation is similar. In my priorapplication, for example, I utilize the compressed air in the workcylinder to carry fuel through a fuel valve into the igniter g5cylinder, and I supply no additional fuel to the work cylinder. Mypresent invention, however, allows additional fuel to be injected intothe work cylinder, and in addition provides specifically for 'anentirely different means and method of supplying a fuel charge to theigniter cylinder. Consequently, the main object of my present inventionis to provide an internal combustion engine wherein all or part of thecharge is ignited before entering a work cylinder, to the end that theigniter cylinder only need be of high compression.

Among other objects of my invention are: To provide an engine utilizingheavy fuel; to provide a heavy oil engine having a relatively lowcompression in the work cylinder; to provide a means and method ofsupplying an igniting charge to alow pressure work cylinder; to providea means and method of supplying fuel to an igniter cylinder; and toprovide an improved means and method of firing a heavy oil engine havinga relatively low working pressure.

My invention possesses numerous other objects and features of advantage,some of which, together with the foregoing, will be set forth in thefollowing description of specific apparatus embodying and utilizing mynovel method. It is therefore to be understood that my method isapplicable to other apparatus, and that I do not limit myself, in anyway, to the apparatus of the 55 present application, as I may adoptvarious other apparatus embodiments, utilizing the method, within thescope of the appended claims.

In the drawing:

Figure 1 is a longitudinal sectional view of a portion of a cylinderhead, and igniter cylinder I embodying my invention.

Figure 2 is a similar view showing another modification utilizing adifierent fuel supply to the igniter cylinder.

In the following description it is to be distinctl0 ly understood thatwhile I have shown and illustrated my invention as applied to a singleair cooled cylinder, it is applicable to any type of engine havingsingle or multiple cylinders, and it is also applicable to internalcombustion engines operating with any of the known cycle relationships.For that reason I have not shown connecting rods, crank shafts, camshafts, or other appurtenances of the engine not related to the presentinvention, as such arrangements are well 20 known to those skilled inthe art.

My invention may be more fully understood b direct reference to thedrawing.

In Figure 1 a cast cylinder head I is provided with air cooling fins 2and preferably a hardened 26 cylinder liner 3. The customary air intakeand exhaust valves utilized for Diesel. operation of an internalcombustion engine have notbeen shown as there are many modifications ofsuch devices and they are no part of the present invention. 80 Bearingon the cylinder liner 3 is a piston 4 provided with the usual rings 5,there being the usual combustion chamber 6 above the top of the piston.

The structure just described, comprising the 85 head I, liner 3, andpiston 4, will be termed hereafter the work cylinder. The piston [isconnected to the crank shaft of the engine in the usual manner.

Inasmuch as I intend to describe my engine as operating with part. ofthe fuel injected into the work cylinder, I provide the cylinder head Iwith a fuel injection nozzle 1, supplied with fuel oil from a source atthe proper time in the cycle through fuel pipe 9. The cylinder head I isalso 45 provided with an igniter channel Ill leading laterally throughan igniter assembly attached to the side of the cylinder head. Thisigniter assembly comprises an igniter casting ll carrying an ignitercylinder body l2 provided with an igniter cylinder liner I4. The ignitercylinder is much smaller than the work cylinder. In the igniter cylinderis a high pressure piston 15 reciprocated in the cylinder through themedium of a divided piston rod l6 joined by an adjusting nut assemblyII. The piston rod l3 terminates in a cam roller assembly l3, the camroller bearing on a cam 23 driven in synchronism with the work cylinderpiston 4 through the usual crank shaft and driving means.

Immediately above the igniter piston I3 is inserted a valve seat 2|,held down by a valve cage 22, the latter being screwed to the upper endof the cylinder liner I4. The valve cage carries a surge valve 24operating in a valve sleeve 23, and forced against the seat 2| by valvespring 23. Valve 24 opens into igniter channel Ill and the valve seat 2|is provided with an ignition aperture 21 opening beneath the valve sothat the contents of the igniter cylinder may be discharged into theigniter channel III, and from thence into the work cylinder. 7

In the modification shown'in Figure 1, however, igniter channel lextends past the surge valve 24, and is continued as a.fuel pressurechannel 33, making a one hundred eighty degree bend, and. opening intothe igniter cylinder below the high point of the igniter piston travelas determined by cam 20. In the fuel pressure channel 33 I position aVenturi block 3| provided with an annular fuel channel 32 openingthrough multiple apertures 33 into the narrowest portion of the venturithus formed. A fuel pipe 34 feeds the annular fuel channel 32.

Inasmuch as it is not important whether the igniter piston I3 ispositively driven or roller driven, as shown, I may prefer to utilize anigniter piston return spring 35 bearing against the lower end of thecylinder liner through the medium of a cylinder spring retainer 36, andmaintained in place by the usual spring retaining disc 31.

I prgfer to operate my engine on the fourstroke cycle system, and as onecomplete up-anddown stroke of the piston is a scavenging movement Iprefer to start my operational description at the beginning of thecharging stroke, after all scavenging has been completed. At some timeafter the firing stroke (the time being at any portion of the completecycle when no great pressure exists in the work cylinder chamber 6, andtherefore in the fuel channel 30), I deposit, by any convenient supplymeans, an ignition charge of fuel in the annular fuel channel 32 throughigniter fuel supply pipe 34. It may be held there in any convenientmanner, such as by a check valve in the fuel pipe. At the same time airis being admitted through the usual air intake valve into the workcylinder, and as the piston 4 starts to rise in the work cylinder theigniter piston I is dropping, due to the contour of cam 20, The suctionproduced immediately closes the surge valve 24, and a slight negativepressure is produced in the igniter cylinder at the same time thatpressure is being built up in the work cylinder. As soon as the descentof the igniter piston uncovers the closed end of fuel channel 30 thereis a surge of air from the work cylinder through the fuel channel 30,and through the venturi, thereby withdrawing the ignition fuel in theannular channel 32 through apertures 33 into the fuel channel andthereafter into the igniter cylinder. The igniter piston then starts torise faster than the work cylinder piston and to compress the fuelcharge in the igniter cylinder against the surge valve 24. I prefer toso adjust the tension of the igniter valve spring and the area of thesurge valve face exposed to'the work cylinder pressure with relation tothe surge valve face exposed to the igniter cylinder pressure, that theigniter cylinder pressure may rise to a point where the igniter fuelcharge is ignited by pressure. This pressure .will vary, according tothe type of oil used, from eighteen hundred to thirty-five hundredpounds per square inch. After ignition the pressure will still riseuntil the pressure developed snaps open the surge valve, and the ignitedcharge will surge into the main combustion chamber. The work cylinder,in the meantime, has had the intake air compressed to a relatively lowpressure, for example, to three hundred fifty pounds per square inch. Atthe same time, or slightly before the ignited charge reaches the workcylinder, I prefer to inject additional fuel through igniter nozzle 1.Both the burning fuel and the injected fuel mix with the air, and flamepropagation is continued in the work cylinder, the ignition beingaccomplishe by the burning injected fuel.

It is obvious that the ignition of the charge in the igniter cylinderand the subsequent surge valve opening can be timed to place the ignitedfuel into the main combustion chamber at exactly the proper time to meetthe auxiliary injected fuel for maximum effect on the work piston 4,usually arriving three or four degrees before the main piston startsdown on the power stroke. At the proper time in the power stroke theexhaust valve opens and the main combustion chamber is scavenged on thenext two strokes as is usual in this type of engine, and the powerstroke is repeated.

In the modification shown in Figure 2 the ignition channel I0 does notextend through into fuel channel 30, and I utilize a separate source ofair entering above the Venturi block 3| through an auxiliary air pipe40. Air may be supplied through this pipe under constant pressureinasmuch as no air will move through the fuel channel 30 except when theigniter piston is in its lowest position as shown in this figure. Whenthe end of the igniter channel 30 becomes uncovered air can rush incarrying with it the fuel from the annular fuel ringv in the Venturiblock. After the piston rises air passage through the channel isautomatically shut off by the piston, and the ignition in the ignitercylinder proceeds as described above.

It is obvious that if desired the entire charge may be injected into thework cylinder from the igniter piston, and in this case I completelyeliminate fuel injection nozzle I. Both methods of operation aresatisfactory, and in either case' the operation of the igniter assemblyis the same, the only difference being the amount of fuel supplied tothe annular ring 32 and the manner in which the device is throttled.

For example, when using an auxiliary injector nozzle 1 the amount offuel supplied to the ignition venturi may be maintained constant, justsufficient to ignite the charge in the cylinder chamber 6. If, however,no auxiliary fuel is supplied, then the charge deposited in the Venturiblock must be varied in accordance with the power demand required fromthe main work cylinder. It is also possible to adjust the air passagesand pressures in such a manner that when the complete charge passesthrough the igniter assembly very incomplete combustion is obtainedtherein, whereas, if a firing charge only is desired a more perfectcombustion can be produced in the igniter cylinder.

My invention has numerous advantages. Preignition of the fuel reducesignition'lag in the work cylinder practically to zero, and apredetermined cycle can be followed. The maximum speed developed by theengine is much greater than that obtained in the usual type of Dieselengine, and the whole cycle of the igniter assembly can be timed to anyadvance or retard in respect to the work cylinder piston movement bychanging the advance or retard of the cam 20 with respect to the crankshaft of the engine. Another important feature is that since the fuelenters the work cylinder already ignited, any desired compression ratiomay be used in the power cylinder, inasmuch as there is no necessity forignition pressures to be developed by the work cylinder piston.

I claim:

1. In an internal combustion engine having a main combustion chambercontaining a piston operating to produce a compression therein, anignition device comprising an auxiliary combustion chamber, a venturiopening into said auxiliary combustion chamber, a fuel reservoir openinginto the throat of said venturi, means for depositing fuel in saidreservoir, means for cyclically supplying compressed air through saidventuri to carry said fuel into said auxiliary chamber, means forcompressing said fuel and air mixture to cause ignition thereof in saidauxiliary combustion chamber by heat of compression, automatic means forreleasing the ignited fuel into said main combustion chamber, and meansfor timing the deposition of fuel in said reservoir during the staticportion of the air supply cycle.

2. In an internal combustion engine having a main combustion chambercontaining a piston operating to produce a compression therein, anignition device comprising an auxiliary combustion chamber, a venturiopening into said auxiliary combustion chamber, a fuel reservoir openinginto the throat of said venturi, means for depositing fuel in saidreservoir, means for cyclically supplying compressed air through saidventuri to carry said fuel into said auxiliary chamber, means forcompressing said fuel and air mixture to cause ignition thereof in saidauxliary combustion chamber by heat of compression, automatic means forreleasing the ignited fuel into said main combustion chamber when thepressure of the burning fuel reaches a predetermined figure, and meansfor timing the deposition of fuel in said reservoir during the staticportion of the air supply cycle.

3. In an internal combustion engine having a main combustion chamberhaving a timed fuel supply and containing a piston operating to producea compression therein, an ignition device comprising an auxiliarycombustion chamber, a venturi opening into said auxiliary combustionchamber, a fuel reservoir opening into the throat of said venturi, meansfor depositing fuel in said reservoir, means for cyclically supplyingcompressed air through said venturi to carry said fuel into saidauxiliary chamber, means for compressing said fuel and air mixture tocause ignition thereof in said auxiliary combustion chamber by heat ofcompression, automatic means for releasing the ignited fuel into saidmain combustion chamber, to ignite the timed fuel supply.

4. In an internal combustion engine having a main combustion chambercontaining a piston operating to produce a compression therein, anignition device comprising an auxiliary combustion chamber, a venturiopening into said auxiliary combustion chamber, a fuel reservoir openinginto the throat of said venturi, means for depositing fuel in saidreservoir, means for passing an air charge through said venturi to carrysaid fuel into said auxiliary chamber, means for compressing said fueland air mixture to cause ignition thereof in said auxiliary combustionchamber by heat of compression, and automatic means for releasing theignited fuel into said main combustion chamber.

5. In an internal combustion engine having a main combustion chambercontaining a piston operating to produce a compression therein, anignition device comprising an auxiliary combustion chamber, a venturiopening into said auxiliary combustion chamber, a fuel reservoir openinginto the throat of said venturi, means for depositing fuel in saidreservoir, means for passing an air charge through said venturi tocarrysaid fuel into said auxiliary chamber, means for compressing saidfuel and air mixture to cause ignition thereof in said auxiliarycombustion chamber by heat of compression, and automatic means forreleasing the ignited fuel into said main combustion chamber when thepressure of the burning fuel reaches a predetermined figure.

6. In an internal combustion engine having a main combustion chamberhaving a timed fuel supply and containing a piston operating to producea compression therein, an ignition device comprising an auxiliarycombustion chamber, a venturi opening into said auxiliary combustionchamber, a fuel reservoir opening into the throat of said venturi, meansfor depositing fuel in said reservoir, means for passing an air chargethrough said venturi to carry said fuel into said auxiliary chamber,means for compressing said fuel and air mixture to cause ignitionthereof in said auxiliary combustion chamber by heat of compression,automatic means for releasing the ignited fuel into said main combustionchamber, to ignite the timed fuel supply.

7. In combination with an engine having a main combustion chamber and anauxiliary combustion chamber containing a piston and an inlet portopening below the top level of the piston travel, a conduit connected tosaid inlet port, a source of compressed air connected to said conduit, aventuri in said conduit, said venturi having an annular fuel ring aroundthe throat of said venturi, said ring having multiple small openingsinto said throat, means for depositing fuel into said ring, said fuelbeing carried into said auxiliary combustion chamber solely by the rushof air through said venturi when said piston uncovers said port, andmeans for creating a static condition in said venturi during fueldeposition.

8. In combination with an engine having a main combustion chamber and anauxiliary combustion chamber containing a piston and an inlet portopening below the top level of the piston travel, a conduit connected tosaid inlet port, said conduit being connected to said main combustionchamber, a venturi in said' conduit, said venturi having an annular fuelring around the throat of said venturi, said ring having multiple smallopenings into said throat, and means for depositing fuel into said ring,said fuel being carried into said auxiliary combustion chamber solely bythe rush of air from said main combustion chamber through said venturiwhen said piston uncovers said port, said fuel being depositcd in saidring only when said port is covered.

HARLAN VERNE HONN.

